What is a cause of humans' negative biological reaction to loneliness?
A、The requirement of family groups.
B、The dependence on social support.
C、The destruction of the environment.
D、The improvement of living conditions.
Nick: Hi, Ryan. Do you know when the test results will come out?Ryan:56()Nick: I'm anxious to see how I did.57()Ryan:I'm not that nervous.58()Nick: I think most of the test was pretty easy, but some of the questions were tricky.Ryan:59()That won't do you any good.Nick:How could you stay so calm all the time?Ryan:60()Nick: You're lucky. I worry all the time.